Straight wire: the next generation.
Frequently, the anticipated results of treatment are not achieved by using preadjusted appliances and straight wires. This is due to inaccurate bracket placement, variations in tooth structure, variations in the maxillary/mandibular relationships, tissue rebound, and mechanical deficiencies of edgewise orthodontic appliances. Clearly, one preadjusted appliance prescription cannot fit all orthodontic patients. Individualized prescriptions for preadjusted orthodontic appliances can be fabricated once all of these reasons are recognized. From the cephalogram and visual treatment objective, the desired position of maxillary and mandibular incisors can be determined according to the maxillary/mandibular relationships. The torque angle of the labial surface of maxillary and mandibular incisors relative to the arch wire plane can be measured with an incisor torque template. The development and refinement of a system to vary the orientation of the bracket arch wire slot relative to the labial surface of each tooth provides a solution to these problems. Beyond the accuracy or inaccuracy of bracket placement and the fact that brackets are placed away from the center of resistance, orthodontic appliances have two additional significant mechanical deficiencies; play between the arch wire and the arch wire slot, and force diminution. These deficiencies cannot be eliminated from current appliances, however, they can be minimized by using reasonably stiff arch wires approximating the size of the arch wire slots. The amount of play plus the amount of force diminution inherent in your appliance can be added to or subtracted from the torque, tip, rotation, and height parameters for each bracket to deliver the teeth to the desired positions. Therefore treatment goals can be achieved with maximum efficiency.